Field of the Invention
The present invention relates to a communication control method, a storage medium, and a printing apparatus, and in particular to a communication control method for controlling communications with USB devices, a storage medium, and a printing apparatus.
Description of the Related Art
There is known a printing system in which a client PC which is a control apparatus sends print data to an MFP which is a printing apparatus, and the MFP performs printing based on the received print data. In this printing system, functions of the MFP are expanded by connecting USB devices having a variety of functions to the MFP. Examples of USB devices include a large-screen extended touch panel, and a multi-function setting menu, a preview image, and so forth are displayed on the extended touch panel. USB over Network technology (hereafter referred to as “USBNW”) is used in a display control process for an extended touch panel of a USB device, and the client PC sends a control signal to the USB device via the MFP, and the USB device displays a setting menu or the like on the extended touch panel based on the received control signal (see, for example, Japanese Patent Publication No. 5745424). A user is allowed to directly operate the USB device. Operating information on user operation is sent from the USB device to the client PC via the MFP, and the client PC sends a control signal, which is for producing a display corresponding to the operation information, to the USB device via the MFP. Namely, signals and information are sent and received between the USB device and the client PC via the MFP. After that, based on the received control signal, the USB device displays a preview image or the like, which corresponds to the user operating information, on the extended touch panel. Here, when the MFP shifts into a power saving mode while the user is operating the USB device, the MFP stops sending and receiving signals and information, and hence the display control process for the extended touch panel of the USB device is hampered. Accordingly, in the printing system, while the USB device is connected to the MFP, the MFP and also the USB device are controlled so as not to shift into the power saving mode.
However, when the MFP and the USB device are controlled so as not to shift into the power saving mode while the USB device is connected the MFP, the MFP and the USB device are in a constant state of being energized irrespective of whether or not the USB device is in use. Thus, even when the USB device is not in use, power is unnecessarily consumed by the MFP and the USB device. Namely, it is conventionally difficult to prevent control over the USB device from being hampered and reduce power consumption at the same time.